I qualified as an adult nurse last year so can also advise if anyone needs help.
Would just like to say in my experience, being a qualified nurse does not automatically mean you can get straight onto a midwifery course. This would be a difficult route to go about it as there are no guarantees at the end of your nurse training that you could get onto the midwifery course. You would still have to apply in all the normal ways through NMAS.
You age and the fact that you already have children is a definite bonus for you as they like people with life experience and people with experience of pregnancy and childcare - hence you can empathise with the women you will be caring for.
As for qualifications, they sound fine. I only had 6 GCSEs but relevant care experience which will also help you. If you have been out of study for a while, an access course at evening school is often a good thing to do first which most universitys would advise. They often like to see recent evidence of study.
Its a hard course to get onto because there are so many applicants and very limited places. Also, be warned, its a hard course with unfriendly shifts on placements, nights, earlys, lates and weekends with lots of essays and exams. Make sure you know what you are letting yourself in for - in my experience, they have no sympathy child-care wise!
Good luck!